Which type of mountain is also called the mountain of denudation?

Step 1: Analyze the question The question asks which mountain type is also called the "mountain of denudation." Denudation means the wearing away of the earth's surface by weathering, erosion, and mass wasting.

Step 2: Explain the concept Mountains are classified by how they form:

• Fold mountains form by compression and folding of crustal rocks (e.g., the Alps, Himalayas, Rockies).
• Block mountains form when land is uplifted between faults (e.g., the Vosges, Black Forest, Horn).
• Volcanic mountains form from the accumulation of lava and ash (e.g., Mount Cameroon, Mount Fuji).
• Residual mountains (also called mountains of denudation or relict mountains) are what remain of older, higher highlands after long periods of weathering and erosion have worn away the surrounding softer rock.

Step 3: Solution The key word is denudation. Only residual mountains are formed by the removal of surrounding material rather than by uplift or volcanic building. The harder, more resistant rock is left standing as mountains or hills. Examples include the Monadnocks, the Cairngorms and Grampians in Scotland, and in Nigeria, inselbergs such as Olumo Rock in Abeokuta and the Idanre Hills.

The other options are formed by constructional (tectonic or volcanic) processes, not by denudation.

Step 4: Answer The correct option is C. Residual mountain.

Step 5: Exam tip Link the words: Denudation = Down-wearing = Residual (what is "left over"). If you see "relict," "mountain of denudation," or "erosional mountain," think residual. Also remember that fold, block, and volcanic mountains are "mountains of construction/upheaval."